1. Field of the Invention
The present invention relates to a flash lighting apparatus capable of controlling the light orientational distribution at the time of flash emission in accordance with the spatially distributional state of subjects, and a camera equipped with the flash lighting apparatus.
2. Related Background Art
Traditionally, when there is not enough illuminance for a subject for taking its photography, a flash lighting apparatus is used to emit a flash light to compensate for the illuminance for the subject.
With a flash by the flash lighting apparatus, a field can be irradiated substantially evenly, and simultaneously, using a TTL adjustment, the flash irradiation amount can be adjusted. Consequently, if the film-to-subject distances are all the same for the subjects in a field, it is possible to take a flash photography with a correct exposure.
Nevertheless, since the flash lighting apparatus irradiates a field evenly, it is impossible to perform a flash photography for all the subjects with a correct exposure if a plurality of subjects are present with different film-to-subject distances in the field as shown in FIG. 1. In other words, a subject in front is in an over-exposure while a subject in the rear is in an under-exposure.
In order to solve this problem, there has been proposed a flash lighting apparatus in which a plurality of flash emission portions are provided to adjust the irradiation amount of each of the light emission portions in accordance with the film-to-subject distances to the respective subjects (as disclosed in Japanese Patent Laid-Open Application No. 1-108538, for example).
However, the above-mentioned flash lighting apparatus is provided with a plurality of flash emission portions. Thus, there is a problem that its mechanical structure is not only complicated, but its mechanism also becomes complicated because each of the light emission portions should be interlocked to make the angles of irradiation changeable.
Also, there is another problem that the electric circuits become complicated because each of the light emission portions where a high voltage is applied must be controlled by a driving unit on the basis of information from a plurality of segmented photometric portions provided for a plurality of the light emission portions.
There is also known an apparatus disclosed in Japanese Patent Laid-Open Application No. 63-115148 as a flash lighting apparatus which controls the light orientational distribution in accordance with the spatially distributional state of subjects. This apparatus is provided with a plurality of flash bulbs in order to perform segmental irradiations for different areas in the image plane of a photographing subject by controlling the light emission or otherwise for each of the flash bulbs.
However, there are problems given below for those conventional flash lighting apparatuses described above.
(1) Due to the necessity of plural flash bulbs and light orientational optical system for each of the light bulbs, the size of the apparatus as a whole tends to be larger and its weight also becomes heavier. PA1 (2) The light emissions of plural flash bulbs require the use of a larger amount of energy. Also, the heat generation is great when they are used in succession. PA1 (3) The plural flash bulbs and light orientational optical system required for each of the bulbs tend to result in the irregularity of light orientations because the overlapping or missing of light irradiation takes place at each boundary between segmented areas. PA1 (4) It is necessary to provide light adjusting circuits for adjusting the respective light emissions of a plurality of flash bulbs. Hence making its control complicated.